Re: m(un)map kmalloc buffers to userspace

From: Michal Hocko
Date: Wed Dec 09 2015 - 08:55:51 EST

On Tue 08-12-15 18:25:31, Sebastian Frias wrote:
> Hi,
> We are porting a driver from Linux 3.4.39+ to 4.1.13+, CPU is Cortex-A9.
> The driver maps kmalloc'ed memory to user space.

This sounds like a terrible idea to me. Why don't you simply use the
page allocator directly? Try to imagine what would happen if you mmaped
a kmalloc with a size which is not page aligned? mmaped memory uses
whole page granularity.
Michal Hocko
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